THE Giuliani ’08 juggernaut just ran head-on into Podhoretz’s First and Last Law of Politics, namely: No politician seeking the nation’s highest office can do as much damage to another as he can do to himself.

John Kerry might be president today if he hadn’t said, “I voted for the 87 billion dollars before I voted against it.” Michael Dukakis must have wondered a million times what might have been had he reacted with some emotion to the nightmare scenario floated by CNN reporter Bernard Shaw about his wife being raped and murdered.

As for Al Gore, the word “sigh” must cause him to break out in hives due to the injury he did himself by sighing and rolling his eyes during the first presidential debate with George W. Bush in 2000.

And during the 36-day Florida recount, you know Bush was quietly eating himself up over failing to reveal in 1999 that he’d been arrested for drunk driving 23 years earlier – because if he had, he’d have avoided the late-hit revelation in the last week of the 2000 election that cost him a few million votes.

And these are all people who won their party’s nomination. What about the candidates who self-destruct during the long season before the nomination is secured?

Well, you got your Joe Biden, who delivered a heartfelt autobiographical speech in 1987 that was actually someone else’s autobiography. You got your Bob Dole, who lost New Hampshire in 1988 and, rather than congratulating the victor, barked on national TV that his rival needed to “stop lying about my record.”

And, of course, you got your Gary Hart, the 1988 frontrunner, daring the media to “put a tail” on him; when they did, they discovered a woman who was not his wife sitting on his knee.

The question before us today is whether Rudy Giuliani committed a blunder of comparable proportions by consenting to a Barbara Walters request for a joint interview with him and his wife Judi – during the course of which he said, embarrassingly, that he would welcome her presence at Cabinet meetings and listen to her closely on issues relating to health care.

Until that moment, he had handled his presidential bid as perfectly as could be imagined – maintaining the enthusiasm of social conservatives even as they learned of his stances on behalf of abortion rights and gun control.

Well, his four months of bliss came to an end when ABC News released the first snippets of the Walters interview last Thursday.

The fact that Rudy was pulled up short in a TV interview naturally leads politically obsessed people to wonder whether this was his “Roger Mudd” moment.

In 1979, Sen. Ted Kennedy decided to challenge Jimmy Carter – the sitting president in his own party – for the Democratic nomination the next year. Kennedy was viewed as something of a secular saint, a heroic legislator of surpassing rhetorical brilliance and skill. That is, until he sat down with Mudd, who asked him, simply, “Senator, why do you want to be president?”

And Teddy Kennedy, that towering genius, couldn’t come up with a single reason. He didn’t become president then, or later, or ever.

Clearly, the Barbara Walters interview isn’t a Roger Mudd moment because Rudy didn’t speak ill advisedly or in a worrisome way on a matter of profound substance. Walters moment only revealed that Rudy is a little too fond of winging it and thought he could say something cute about his wife that really wasn’t cute at all – and seemed perhaps more about currying favor with her than about finding the appropriate balance between portraying a loving marriage and depicting a future presidency.

Of course, what Rudy was doing with Barbara Walters was an effort to deal with a troublesome issue early – to neutralize the damaging effect of his marital history by being open and clear and honest. He did that well, actually, or as well as anyone could possibly do. And then he muffed it.

News of the Walters interview began a 96-hour ordeal for Giuliani that included the leak of his grand-jury testimony in the case of his former police commissioner’s ties to a crooked contractor – potentially his most serious liability – and the revelations that Judi Giuliani has actually been married more than twice and had worked for a medical-equipment firm that used (and thus killed) dogs.

It was inevitable that Giuliani was going to hit some major bumps along the way. Maybe he’s lucky he hit them now, even though they’re bound to take a toll on his poll numbers (and perhaps solidify Fred Thompson’s decision to run for the presidency).

We’ll know more when we see how well he does during this time of troubles.